Arthur Greeves was a boyhood friend of Lewis’s, one with whom he corresponded throughout his life. It’s in those letters that we see the transformation of Lewis from an atheist/agnostic to a convinced Christian, and we witness an ongoing theological discussion over the years.
One of those discussions, in 1947, centered on the nature of the spiritual body Christians would receive in eternity. Lewis takes issue (in love, of course) with Greeves’s speculation about it.
I agree that we don’t know what a spiritual body is. But I don’t like contrasting it with (your words) “an actual, physical body.” This suggests that the spiritual body wd. be the opposite of “actual”—i.e., some kind of vision or imagination. And I do think most people imagine it as something that looks like the present body and isn’t really there.
I believe Lewis is correct in that assertion. We have this vague, shadowy concept of the nature of a spiritual body that might more approximate the idea of a ghost than what Scripture really indicates. For evidence, Lewis notes,
Our Lord’s eating the boiled fish seems to put the boots on that idea, don’t you think? I suspect the distinction is the other way round—that it is something compared with which our present bodies are half real and phantasmal.
Those who are familiar with Lewis’s writings will automatically think of his fantasy entitled The Great Divorce. In it, passengers on a bus ride from hell to heaven arrive, only to find that they are like phantoms compared with the reality of heaven. They can see through each other; the grass is so hard the can barely walk on it without pain; any attempt to pick up a piece of heavenly fruit is virtually impossible.
Lewis often used fantasy to make a valid theological point: even though what we experience now is certainly real, it is not the ultimate reality. That which awaits us in the heavenly realm is so much more real that we will look back on our earthly life and perhaps wonder how we could have thought it was all there was.
Like Lewis, I can’t fully explain what the new me will be like in my resurrected state, but also with Lewis, I can affirm that it will be far greater than anything I can now imagine.